Apache2 with PHP FallbackResource doesn't work when Request-URI is / and encoding is gzip

[Giovanni Lovato]

Installed packages:
apache2-mpm-prefork (2.2.22-6ubuntu2.2)
libapache2-mod-php5 (5.4.6-1ubuntu1.2)

Steps to reproduce:
1. Allow option override on /var/www
2. Remove /var/www/index.html
3. Create /var/www/index.php with any content (e.g. <?php echo $_SERVER['REQUEST_URI']; ?>)
4. Create /var/www/.htaccess with FallbackResource /index.php
5. Go to http://localhost/any -> it works, index.php is called
6. Go to http://localhost/ -> empty response, something went wrong

Either disabling FallbackResource or gzip encoding solve the issue, so I assume is the combination of the two to cause the problem.

[Giovanni Lovato (heruan)]

Having "DirectoryIndex index.php" on the .htaccess file solves the issue. It seems the default Apache DirectoryIndex is causing the problem when index.php is not the first default index document.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Adrien Béraud (wagaf)]

This bug breaks many websites.